Volume 9, Issue 1 p. 21-28

THE MOST RELIABLE COMPOSITE WITH A SPECIFIED TRUE SCORE

MAX A. WOODBURY

MAX A. WOODBURY

George Washington University

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FREDERIC M. LORD

FREDERIC M. LORD

Educational Testing Service

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First published: May 1956
Citations: 13

This project has been supported by the Officeo f Naval Research under Contract N6onr-270-20 and by the National Science Foundation, Grant NSF G-642. The basic mathematical derivation is the work of the senior author. The authors are indebted to Professor Harold Gulliksen for his encouragement and penetrating comments on a draft of the manuscript.

Abstract

If a composite score is to be obtained from a battery of tests, the manner in which these tests enter into the composite may be varied in two respects: (a) different weights may be assigned to the tests, and (b) the test lengths (and correspondingly the administration times) may be altered. Weights and administration times may be assigned so as to maximize either the validity or the reliability of the composite. The present paper comments briefly on the problem of maximum validity, and then presents a simple method for maximizing reliability.